Methods for producing shape holding products of various shapes from slack mercerized stretchable cotton fabrics by molding them

ABSTRACT

CELULOSIC FABRICS ARE SUBJECTED TO A SHRINKING TREATMENT SUCH AS SLACK MERCERIZATION TO IMPART ELASTICITY THERETO AND THEN IMPREGNATED WITH A CROSS-LINKING AGENT; PLACED ON A MOLD; STRETCH-MOLDED AND HEATED IN THE MOLDED CONFIGURATION TO EFFECT CROSS-LINKING AND SET THE MOLD CONFIGURATION.

United States Patent 3,625,643 METHODS FOR PRODUCING SHAPE HOLDING PRODUCTS OF VARIOUS SHAPES FROM SLACK MERCERIZED, STRETCHABLE COT- TON FABRICS BY MOLDING THEM Albert S. Cooper, Jr., Metairie, Albert M. Walker, New

Orleans, and William G. Sloan and George F. Ruppenicker, Jr., Metairie, La., assignors to the United States of America as represented by the Secretary of Agriculture No Drawing. Filed Mar. 29, 1963, Ser. No. 269,216 Int. Cl. D06m 13/12, 13/34 US. Cl. 8--116.3 8 Claims ABSTRACT OF THE DISCLOSURE Cellulosic fabrics are subjected to a shrinking treatment such as slack mercerization to impart elasticity thereto and then impregnated with a cross-linking agent; placed on a mold; stretch-molded and heated in the molded configuration to effect cross-linking and set the mold configuration.

A non-exclusive, irrevocable, royalty-free license in the invention herein described, throughout the world for all purposes of the United States Government, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.

This invention relates to methods for producing shapeholding products by molding chemically treated cotton materials.

In the literature the topic of molding has existed for about one hundred years. Molding has been applied to many and and varied materials, the most common being rubber, metals, and resinous substances. In the May 1962 issue of Modern Textiles Magazine, an organ of the A.A.T.T., R. P. Nirenberg briefly explains Methods of Molding Fibers and Fabrics for Moulding and, Where the Molded Fabrics Can Be Profitably Used. The emphasized molding processes and techniques described by this author parallels common knowledge employed by the plastics industry, and deals with the utilization of physcal means to obtain molded products. The literature suggests a 75 to 80% thermoplastic fiber content with non-thermoplastics as a must for satisfactory molding. This idea in combination with other knowledge pointed the way to the investigation which lead to our invention.

Our invention relates to the use of some of the commonly employed methods and physical means, supplemented by the incorporation of chemical substances which impart thermoplastic qualities to cotton fibers, finally yielding molded cotton goods. In part, our invention also relates to US. pending application Ser. No. 244,838, filed Dec. 14, 1962, now US. Pat. No. 3,285,- 690. However, the utility of the filed application deals with the production of cotton fabrics with elastic recovery and dimensional stability. The utility of the present invention deals with a method for producing shape-holding ice products molded from woven, knitted, or non-woven fabrics made from cotton.

"Basically, this invention consists of the treatment of cotton with a shrinking agent, the molding of the shrunken cotton material, and varied subsequent steps which may consist of application of heat, or addition of a cross linking resin for creaseproofing cellulose followed by heat treatments. The sequence of steps can be altered to fit the needs of the article to be molded, but without eliminating the use of a shrinking step in combination with the molding operation, since it is of vital significance.

The normal elongation of untreated woven cotton fabrics at the breaking point is about 10% in many instances. Variables are introduced into fabrics through construction of the fabric, yarn count of the fabric, maturity of the cotton, twist, etc. In a typical case an untreated x 80 cotton print cloth if 'wetted and molded will burst at any region Where elongation exceeds 10%. On the other hand, if the molding elongation introduced by the configuration of the mold, does not exceed 10% the fabric will revert to its original fiat shape upon rewetting in a relaxed state.

The normal elongation at the breaking point of slack mercerized cotton can be from v25 to There is a summation of percent shrinkage to the normal 10% stated above, which yields higher elongation values. These higher elongation values incurred success to our investigative work. However, the molded cotton in this case will neither hold its configuration fully nor flatten out when wetted with water. The molded shape is held with only a marginal loss.

The normal elongation at the breaking point of slack mercerized cloth which has been resin treated with a cross linking agent may vary due to one, or a combination of factors such as curing temperature, degree of substitution, or order of application of the chemical agents. However, the value of adding a chemical agent which will cross link cotton in its molded state lies in that the final product will tend to hold its shape with no loss of configuration upon rewetting.

Briefly, the significant difference between a cotton mercerized-molded fabric and a cotton mercerized-resin treated-molded article is one of degree. Specifically, a cotton mercerized fabric which has been molded to the shape of a brassiere cup with a crown height of 10 cm. will recover to 9 cm. upon rewetting, while the cotton fabric which has been mercerized and cross linked with a resin for creaseproofing cellulose will yield a cup with a crown height of 10 cm., which will recover to 9.9 cm. upon rewetting. The latter is our preferred process.

A cross linking chemical substance for creaseproofing cellulose is excluded from the process when a molded article of maximum strength is desired. Most of the commercially available cross linking resins for creaseproofing cellulose introduce a loss of tearing strength, which is even more evident at the higher curing conditions of the treated cottons.

Four operative procedures have been sifted from the available data obtained through investigation. The steps are tabulated below as action upon the cotton fabrics to produce molded, shape-holding brassiere cups, which will withstand laundering without loss of the molded shape.

TABLE Procedure Stcp A B O D 1 Shrink Shrink Shrink Shrink. 2 Wash and dry (no tension) Heat mold Placle:1 on cold mold and mold, Wash (no tension).

co 3 Apply tlzlrolsslinking agent for creaseproot- Place on hot mold Wash on mold Heat mold.

ng ce u 050. 4 Place on hot mold Dry on mold (above 160 C.) Dry on mold (above 160 Place on hot mold. 5 Mold and cure Wash and dry (on or of? mold) Dry on mold (above 160 C.) 6 Wash and dry (on or oil mold) Selection of the specific construction of type of cotton fabric for the particular molded shape desired is essential in all cases. A mold that requires equal stretching of the fabric in both warp and filling directions requires a fabric that shrinks equally in each direction. Similarly, molds requiring uneven stretch require fabrics that shrink unequally in respect to warp and filling directions. Also the twist of the yarns, and an open fabric construction must be suitable to obtain the desired shrinkage.

Articles that can be molded into shape-holding products by the processes of our invention include the following: caps, and cap liners, hat and hat liners, upholstery, toy animals, product housings, protective packaging, gloves and glove liners, brassiere cups, foundation garments, bathing suits, shoes and shoe liners, coats, liners for coats and overcoats, plastic laminates, etc.

Although it is economical at this time to utilize sodium hydroxide as a shrinking agent, this need not be considered as the only agent for such purpose. There are other shrinking agents, which will serve the purpose.

The mercerizing strength of sodium hydroxide can be defined as a percent by weight between 13% and 35%; however, temperature and other factors aifect these limits. Nevertheless, in utilizing sodium hydroxide as a shrinking agent these mercerizing strengths yield the maximum shrinkage desired.

EXAMPLE 1 A 90 x 90 combed percale was slack mercerized, washed and dried without tension. Approximately 30% shrinkage in each direction was obtained. The shrunken fabric was saturated with a solution of dimethylolethylene urea as the crosslinking agent for creaseproofing cellulose, containing a 0.5% wetting agent, and a 1.5% catalyst. The fabric was hydroextracted to a wet pickup of 70%. The fabric was then molded over a brassiere cup mold, and heated to 160 C. so that the cup diameter was 6 inches and the crown height was 3 inches. After drying for 3 minutes on the heated mold the fabric was removed, and oven-cured for an additional 3 minutes at 160 C. The molded fabric was then washed and dried, off the mold. The cup dimensions were stable on subsequent home laundering and tumble drying. (See Procedure A.)

EXAMPLE 2 The process of Example 1, using 48 x 48 sheeting, was employed. The shrinkage obtained was 25%. The diameter of the cup was 3 in., and the crown height was 1% inches. (See Procedure A.)

EXAMPLE 3 The process of Example 1, using 80 x 72 print cloth, was employed. Approximately the same shrinkage and cup size as in Example 1 were obtained. (See Procedure A.)

EXAMPLE 4 A 43 x 41 wafiie weave fabric was slack mercerized. Approximately 45% shrinkage in both the warp and filling directions was noted. The fabric was hydroextracted to a wet pickup of about 100%. The fabric was then molded over a heated brassiere cup mold at 160 C. without washing out the caustic soda, so that the cup diameter was 4 inches, and the crown height 3 inches. After drying for 3 minutes on the hot mold at 160 C. the fabric was then removed, washed, and acid soured. The crown height receded to 2.7 inches (Procedure B). The brassiere cup was dried on the mold.

EXAMPLE 5 A 43 x 41 waiile weave fabric was employed with the process of Example 4, and a 45 shrinkage in warp and filling directions was noted. The process varied in that the brassiere cup was molded cold, so that the fabric was restretched to original construction in the molded area. The crown height was 4 inches, and the diameter was 4 inches. The cup was washed on the mold, and dried on the mold, also. The crown height receded to 3.6 inches (Procedure C).

EXAMPLE 6 A 43 x 41 watiie weave fabric was slack mercerized, and washed without tension. A shrinkage of 45% was noted in both directions. The fabric was placed on the heated mold, and restretched to a crown height of 4 inches, and a diameter of 4 inches. Time on mold Was 3 minutes at C. On subsequent washing and tumble drying the crown height receded to 3.6 inches (Procedure D).

We claim:

1. A process for molding a cotton fabric to produce a shape-holding product comprising:

(a) slack mercerizing and shrinking the cotton fabrlc to the maximum possible degree with an alkaline mercerizing agent which causes shrinkage and increases the stretchability of said fabric above that of the untreated cotton fabric;

(b) washing and drying the shrunken fabrlc without tension;

(c) applying an aqueous solution of a cross-linking resin for creaseproofing cellulose to the washed and dried shrunken fabric in an amount sufiicient to stabilize said fabrics dimensions;

((1) placing said resin treated fabric on the mold;

(e) stretch molding said treated fabric by stretching it on the mold beyond the stretchability of the untreated cotton fabric and dry curing the resin treated fabric by energizing the mold with heat at a temperature of at least 160 C.; and

(f) washing and drying the molded fabric.

2. The process of claim 1 wherein the alkahne mercerizing agent which causes shrinkage is sodium hydroxide of mercerizing strength.

3. A process for molding a cotton fabric to produce a shape-holding product comprising:

(a) slack mercerizing and shrinkage the cotton fabric to the maximum degree possible by wetting it with an alkaline mercerizing agent which causes shrinkage and increasing the stretchability of said fabric above that of the untreated cotton fabric;

(b) heating the mold to a temperature of about 160 C.;

(c) placing the wet fabric on the heated mold;

(d) stretch molding said wet fabric by stretching it on the mold beyond the stretchability of the untreated cotton fabric drying the fabric on the mold at a temperature of at least 160 C. until the water content of the fabric is less than about 7%;

(e) Washing the molded fabric free of the chemical shrinkage agent; and

(f) drying the molded fabric.

4. The process of claim 3 wherein the alkaline mercerizing agent which causes shrinkage is sodium hydroxide of mercerizing strength.

5. A process for molding a cotton fabric to produce a shape-holding product comprising:

(a) slack mercerizing and shrinkage the cotton fabric to the maximum degree possible by wetting it with sodium hydroxide solution of mercerizing strength and increasing the stretchability of said fabric above that of the untreated cotton fabric;

(b) placing the wet fabric on the mold and stretch molding it on the unheated mold beyond the stretchability of the untreated cotton fabric;

(c) washing the molded fabric free of the sodium hydroxide solution on, and under tension of, the mold; and

(d) drying the molded fabric on the mold at a tempera ture of at least 160 C. until the water content of the fabric is less than about 7%.

6. A process for molding a cotton fabric to produce a shape-holding product comprising:

(a) slack and mercerizing and shrinking the cotton fabric to the maximum degree possible by wetting it with sodium hydroxide solution of mercerizing strength and increasing the stretchability of said fabric above that of the untreated cotton fabric;

(b) washing the shrunken fabric without tension;

(c) heating the mold to a temperature of about 160 ((1) placing the wet fabric on the heated mold; and

(e) stretch molding said wet fabric by stretching it on the mold beyond the stretchability of the untreated cotton fabric drying the fabric on the mold at a temperature of at least 160 C. until the water content of the fabric is less than about 7%.

7. A process for producing a molded cotton fabric having shape-holding properties comprising shrinking the cotton fabric to the maximum degree possible by wetting it with an alkaline mercerizing agent capable of cansing shrinking thereof and increasing the stretchability of said fabric above that of the untreated cotton fabric, washing and drying the shrunken fabric without tension, applying an aqueous solution of a cross-linking resin for creaseproofing cellulose to the shrunken fabric, and stretch molding said resin treated fabric by stretching it on the 6 mold beyond the stretchability of the untreated cotton fabric and dry curing the resin treated fabric at a temperature of at least 160 C. to a desired shape.

8. A process for molding a cotton fabric to produce a shape-holding product comprising:

(a) shrinking the cotton fabric by slack mercerizing it to obtain about 30% shrinkage in each direction and increase the stretchability of said fabric above that of the untreated cotton fabric;

(b) washing and drying the shrunken fabric without tension;

(c) applying a cross linking resin for creaseproofing cellulose to the washed and dried shrunken fabric by saturating it with a solution containing about 10% dimethylolethylene urea as the cross linking resin, about 0.5% Wetting agent, and about 1.5% catalyst, and hydroextracting the thus-saturated, resin-treated fabric to a wet pickup of about (d) placing the hydroextracted resin-treated fabric on the mold;

(e) stretch molding said treated fabric by stretching it on the mold beyond the stretchability of the untreated cotton fabric and dry the resin-treated fabric by energizing the mold with heat at a temperature of at least C. for at least 3 minutes; and

(f) washing and drying the resulting molded fabric.

References Cited UNITED STATES PATENTS 1,509,920 9/1924 Bacon et al. 8-1156 X 2,205,120 6/1940 Heberlein et al. 8-1164 2,926,414 3/1960 Weiss et al. 8-125 X 3,145,132 1/1964 Seltzer 8-125 X 3,227,511 1/1966 Seltzer 8-125 X FOREIGN PATENTS 462,899 3/1937 Great Britain.

0 GEORGE E. LESMES, Primary Examiner H. WOLMAN, Assistant Examiner 

